Some more thoughts on selecting the correct mag for starting -

The impulse function on a mag provides a both a substantial timing
delay and a velocity enhancement for starting purposes. Both are
important. The timing delay of the impulse prevents an engine from
kicking back. That's why starting is done on one (the impulse) mag
only. Most aircraft have only one mag with an impulse, but even a
non-impulse mag may generate a spark at cranking speeds if the mag is
in good condition.

Two things to consider are

1) Be sure the only correct mag is selected if hand propping - and
never put your fingers over the back of the blade. I didn't once on a
TriPacer and still have a fortunately small scar on the tip of my index
finger when it kicked back mightily.

2) Consider that possibly the mag p leads might get reversed in
maintenance. The starter may be able to handle the cranking on the
wrong mag but it could be a hand propping accident waiting to happen.

That's why I won't hand prop a strange airplane for the first time.